The present invention relates to plant extracts useful as modulators of hair growth during conditions of hair loss.
Normal scalp hair loss can be caused either by a physiologic pattern of aging or to a genetically controlled trend of non-scarring hair loss, named androgenetic alopecia. The hair loss of aging evolves as a slow process in middle-aged and elderly subjects, as a generally diffuse gradual and progressive hair thinning and loss from most of the hairy scalp. Contrary to the previous etiology, androgenetic alopecia develops earlier, even in 18 years old subjects, develops rapidly and involves specific temporal hair loss in male type, or vertex hair loss of female type androgenetic alopecia. In addition to the physiologic hair loss, various etiologies may cause hair deprivation, e.g. immune diseases (alopecia areata), pharmacological drugs (heparin, lithium) or diseases (fungal).
Generally, the hair follicle and resulting hair shaft are in continuous growth and involution, and develop in three general stages: anagen, the growth phase of about 3 years, catagen, a transitional 3 weeks phase of development preceding the catagen phase, an involution of the hair follicle lasting about 3 months, afterwards the hair starts its cycle again.
Various treatments were suggested for hair loss, such as                i) Topical minoxidil (U.S. Pat. No. 4,596,812) at concentrations from 1-5%, with an improvement in hair loss in about ⅓-⅔ of patients (Koperski et al, 1987). At the more effective higher concentrations, it cannot be used in women and may cause hypotension or hypertrichosis.        ii) A relatively new indication for the antiprostatic drug Finasteride (U.S. Pat. No. 4,760,071), improves hair loss after at least one-year daily uptake of the drug. Claims a 60% success as compared with 39% hair growth in control group, but without broad clinical evidence of efficacy and side effects, i.e. impotence.        iii) A variety of plant extracts were proposed as hair growths stimulants. Most of the data has not published in peer reviewed medical literature. Part of it is referred in various patents, e.g. U.S. Pat. Nos. 5,750,107 and 4,769,231, and European Patent EP 584365. Said plant extracts are, for example, grape seed, ginseng, jojoba, kola, lavender, swertia, guarana or saw palmetto.        iv) Other remedies, which possess a low efficacy or cause high side effects, are spironolactone, acetylcholine derivatives, estradiol, nicotinic acid amide, nicotinic acid, benzyl nicotinate, glycyrrhizinic acid, cyclosporin and prostaglandin analogues.        v) Unproven treatments are those with Vitamin E, Vitamin B6, biotin, pantothenic acid, amino acids such as arginine, capronium chloride, hinokitiol, serine and methionine, organic acids or oils.        
Thus, an effective treatment of hair loss is required. The treatment should be effective at least as minoxidil, without having inherent hypotensive properties and be available for women as well. Preferably, the ideal treatment should not inflict the psychological effect of long-term drug ingestion or induce low patient compliance due to long-term use.